Field effectiveness of improved hermetic storage technologies on maize grain quality in Central Mexico

Maize is the main crop cultivated by small scale farmers (SSF) in Mexico, and its production represents an important goal for local food security. However, SSF very often face severe post-harvest losses in maize, mainly because of insect pests and the lack of suitable storage technology. This study was conducted to compare the field effectiveness in terms of maize quality under on-field conditions of SSF of two improved hermetic storage technologies with the traditional storage. The field experiment was performed on-farm in the highlands of Central Mexico. Maize grains were stored in three storage devices: hermetic plastic bag (sBag), hermetic plastic silo (Bioxilo), or traditional polypropylene sacks. The study considered the quantitative evaluation of storage, physical, nutritional, and industrial qualities of maize after 4, 8 and 12 months of storage. Environmental conditions of storage such as oxygen levels, temperature and humidity were monitored. After 1 year of field storage, compared with traditional sacks, sBag and Bioxilo showed a significant lower losses in storage due to insects. When controlled infested maize by artificial insect infestation methods was used, the improved technologies were also effective in reducing grain losses. Furthermore, both sBag and Bioxilo prevented grain quality detriment in terms of physical, nutritional and industrial (for tortilla and seed) properties (p < 0.01). Additionally, compared with traditional storage, sBag and Bioxilo showed efficient control of the hermetic conditions in terms of oxygen, temperature and humidity, but no significant differences were detected between the two improved technologies. In summary, under on-farm conditions, the successful preservation of maize grain quality was achieved by the improved sBag and Bioxilo in the highlands of Mexico. In the future, positive effects of this storage system will need to be validated under tropical conditions.     

Analysis of the spatial distribution and dispersion of Plodia interpunctella (Lepidoptera: Pyralidae) in South Korea

This study proposes a novel method to predict the spatial dispersion of Plodia interpunctella by considering the climatic conditions and location of agricultural storage facilities. To accomplish the study objectives, a rearing experiment was conducted, and the CLIMEX model was used to evaluate the climatic suitability of P. interpunctella based on the model parameters estimated from the direct rearing experimental results, in addition to the previous rearing data. Subsequently, we evaluated the distances between the agricultural storage facilities [represented by rice processing complexes (RPCs) and agricultural product processing centers (APCs)] and main ports of grain entry by calculating the flight distance of P. interpunctella. As a result, the climate of South Korea was found unsuitable for P. interpunctella, but the suitability increased throughout the country when considering the indoor temperatures of storage facilities. The analysis of its dispersion with the consideration of grain entry ports, RPCs, and APCs showed that P. interpunctella could be dispersed to areas near storage facilities within 10 d by flying after its first introduction into the ports, as estimated by the calculated flight distance of 32.5 km. However, its dispersion could be accelerated by grain delivery and reach the farthest point in a day. This study provides a methodology to combine species distribution modeling with geographic information system, besides providing a possible scenario of P. interpunctella dispersion, which could serve as the fundamental data for establishing an adequate control strategy.     

Low seed moisture and polythene packaging improve storability of seed paddy

Rapid loss of seed germination and vigor during storage is a common problem faced by rice farmers and seed producers. Present study investigated the influence of packing material and seed moisture content (SMC) at packing on seed germination and vigor during storage in rice. Seeds of three popular improved rice varieties were stored in polythene and poly-sack (woven polyethylene) with 11% and 13% SMC at packing. Standard seed germination (SSG), glasshouse seedling emergence (GSE) and seed vigor as measured by field emergence (FE) were recorded at monthly intervals in storage. Seed germination and vigor could be maintained unchanged for the longest duration in polythene at 11% SMC. In Bg 300, SSG remained unchanged for 11 months, GSE for >11 months and FE for 10 months. In Bg 352 and Bg 358, SSG remained the same for eight months, GSE for 10 months and FE for nine months. Therefore, polythene is a better alternative to poly-sack which is the commonly used material at present and SMC 11% is better than 13% for storage of seed paddy in polythene.     

Mitochondrial response of the lesser grain borer Rhyzopertha dominica (F.) to modified atmospheres

Rhyzopertha dominica is an insect pest that feeds on a wide variety of grains and stored cereals, producing economical losses. Bioenergetics studies on insects are necessary to eventually plan strategies to reduce pest infestation on stored grains with methods other than insecticides. Modified atmosphere treatments, where insects are exposed to either low O₂ or high CO₂ concentrations, or both, can be used as alternatives. In this research, R. dominica was subjected to a modified atmosphere environment (MA) consisting of 5% O₂ and 10% CO₂ for 24 h and was compared with normoxia insects (21% O₂ and 0.02% CO₂). Mitochondria from the whole insect were isolated and their protein content was analyzed by two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) using OFFGEL Fractionator equipment and 12% polyacrylamide gels electrophoresis (SDS-PAGE). Lactate concentration, cytochrome c oxidase (COX) and ATPase activities were measured. Lactate concentration was 29% higher in R. dominica exposed to MA versus normoxia. 2-D PAGE and LC MS/MS revealed the presence of a heat shock protein (hsp60), an actin fragment, and ATP synthase α and β catalytic subunits. Activity levels of COX and ATPase were reduced by 58 and 59%, respectively, in MA versus normoxia. Therefore, R. dominica may have shifted into a hypo-metabolic state because oxygen intake was insufficient to maintain enzymatic activity. This scenario would ultimately result in a decrease in substrate concentration (oxygen) and a reduction in electron transport chain complex activity. Thus, eventually, this knowledge can be use to develop novel environmentally friendly alternatives to eradicate or reduce pests in stored grains.     

Assessment of Rhyzopertha dominica (F.) progeny and feeding damage on rice dried with infrared radiation

Infrared radiation (IR) is a method of drying grains that eliminates insect and microbial pests. It is unknown if IR could cause grains to be more susceptible to insects. Thus, the effects of IR on Rhyzopertha dominica development and feeding damage using long-grain rice varieties, Clearfield XL745 (hybrid) and CL152 (pureline), were examined. Rough rice was dried with three IR intensities: 2.15, 2.83, and 10.84 kW/m². The number of progeny developed, feeding damage, and frass weight after IR-drying were compared with air-drying methods for rough rice and rice milled to brown rice after drying. Since R. dominica develop internally, X-ray technology was used to examine internal progeny and feeding damage. Progeny development and kernel damage appeared to be more affected by fraction (brown rice) than the cultivar of rice or intensity of IR used, with more progeny produced on brown rice than rough rice. An IR intensity of 10.84 kW/m² increased the number of overall progeny, the amount of adults, and frass produced on CL152 brown rice. An intensity of 10.84 kW/m² also increased the amount of larvae observed for both varieties and fractions. The intensity of 10.84 kW/m², under the conditions of this study, is not recommended for drying rice.     

Deployment of an attractive toxic sugar bait system (ATSB) with insecticide,for adult Tribolium castaneum (Coleoptera: Tenebrionidae)

Tribolium castaneum is a critical stored-grain pest of nuts and cereals. Insecticides have traditionally been used to control it; however, their overuse can result in the development of insecticide resistance. Effective bait pesticides could be useful tools for slowing down the rate of insecticide-resistance development and improving the management of stored grain pests. Attractive toxic sugar bait (ATSB) systems are used with mosquitoes and flies; they lure pests with liquid foods that contain sugars but also an oral toxin. It is unknown whether the ATSB system is applicable to T. castaneum adults who prefer dry food products with reduced water content. The objective of this study is to develop an optimal ATSB system for T. castaneum control. Thus far, it found that T. castaneum consumed a gypsum block. The dietary intake of T. castaneum adult beetles was facilitated with added mannitol into gypsum block. Combining insecticides that are oral toxins of the pests with these facilitating sugars results in the death of the pest. Spirotetramat causes a significant reduction in fatty acid biosynthesis by inhibiting acetyl-CoA carboxylase. In this investigation, we have demonstrated that spirotetramat, at low concentrations, was lethal to T. castaneum adults, when used with the ATSB system, combined with mannitol. The lethality of chlorfenapyr, an inhibitor of mitochondrial ATP synthesis, to adult T. castaneum did not increase when used in the ATSB system with mannitol. These results show that the active ingredient used in the ATSB system is integral for beetle control. Increasing the oral delivery rate of insecticides using carbohydrates leads to increased lethality rates of stored-grain pests.     

Two lysozymes are involved in the larva-to-pupa transition and the antibacterial immunity of Lasioderma serricorne (coleoptera: Anobiidae)

Lysozymes play important roles in the innate immune response against pathogen infections of insects. In this study, i-type and c-type lysozymes (LsLysI and LsLysC) were identified from the cigarette beetle, Lasioderma serricorne. Both genes were highly expressed in late larvae and pupae, especially in the fat body and integument. The expression of LsLysI and LsLysC was induced by 20-hydroxyecdysone. The expression levels of both LsLys genes were significantly upregulated after peptidoglycan (PGN) exposure and gram-positive bacterium Staphylococcus aureus infections. RNA interference (RNAi)-mediated knockdown of LsLysI or/and LsLysC in 5th instar larvae reduced lysozyme levels and disrupted the larva-to-pupa molt. Knockdown of LsLysI or LsLysC alone, and co-suppression of both genes, increased larval mortality by 13.3%, 21.1%, and 43.3% after S. aureus infection. The results demonstrated that LsLysI and LsLysC play key roles in a successful larva-to-pupa transition and in the innate immune response of L. serricorne.     

Effects of interaction between rice glutelin and starch on starch gelatinization in a simulated storage system

Starch and protein are the two major components of rice and interaction between them will occur during storage. However, whether the interaction between starch and protein impacts rice starch gelatinization is still unclear. In this study, the effects of starch-protein interaction on starch gelatinization (japonica rice) were investigated using a glutelin–starch simulation system under high temperature and humidity storage conditions. A glutelin–starch ratio of 1:4 was used in the simulation system and stored in an artificial climate chamber (40 °C, 60% humidity) for 60 d. The interaction had a significant effect on starch gelatinization. Starch granule particles were broken down, and the bonds of starch granules weakened during interaction with glutelin. The secondary structure of glutelin loosened, as the starch disintegrated the α-helix structure. Correlation analyses revealed that peak viscosity (PV), trough viscosity (TV), and final viscosity (FV) had a significant negative correlation with carbonyl content, and disulfide bonds (P < 0.01), as well as a significant positive correlation with the active thiol content (P < 0.01). Moreover, setback (SB) had a significant positive correlation with the α-helix and a negative correlation with the β-turn content (P < 0.05). PV, TV, breakdown (BD), and FV were significantly related to β-sheet in glutelin (P < 0.05). These results suggest that glutelin and starch can interact and affect starch gelatinization.     

Development of resistance in stored grain pest,Trogoderma granarium (Everts) against deltamethrin and its effective control by synergistic toxicity of bifenthrin and chlorpyrifos

The current investigation was conducted to estimate the resistance level against deltamethrin in fourth and sixth instar larvae of Trogoderma granarium collected from wheat storage warehouses of Dera Ghazi Khan (DGK), Okara (OKR) and Gujranwala (GUW). Results showed that the fourth and sixth instar larvae of collected strains warehouses moderately resistant to deltamethrin compared with the same developmental stages of insecticide susceptible laboratory strain (LAB-S). Efficacies of bifenthrin, chlorpyrifos and their various combinations were analyzed against fourth and sixth instar larvae of different strains of pest populations to minimize the development of resistance against deltamethrin. LC_50s of bifenthrin against fourth and sixth instar larvae of all the four populations were recorded at low concentrations compared to deltamethrin. The LC₅₀ values of bifenthrin against fourth instar larvae of LAB-S, DGK, OKR and GUW populations were 359.32, 416.58, 524.01 and 598.91 ppm, respectively, while these values were 204.30, 262.98, 301.89 and 355.22 ppm against sixth instar larvae of those populations, respectively. Chlorpyrifos was found to be the most effective insecticide compared to bifenthrin and deltamethrin. The LC₅₀ values of chlorpyrifos were 189.33, 305.37, 376.30 and 459.15 ppm against fourth instar larvae of LAB-S, DGK, OKR and GUW populations, respectively, whereas for sixth instar larvae those values were 98.24, 129.61, 163.43 and 230.74 ppm, respectively. Various combinations of bifenthrin and chlorpyrifos viz., 1:1, 2:1, 3:1, 1:2 and 1:3 were also tested. Based on the values of LC₅₀ and relative toxic unit, 1:3 combination was observed as the most effective among all combinations. The LC₅₀ values of fourth instar larvae of all the four populations against each insecticide and their combinations were recorded at high concentration compared to that of sixth instar larvae. Results of current investigation need to be considered in present stored grain insect pest control program of warehouses in Punjab¹.     

The prevalence of keratoconus in northern Poland: A cross-sectional study of patients from a primary healthcare practice

IntroductionKeratoconus is defined as central and/or paracentral corneal thinning and steepening with consequent irregular astigmatism. To date, no prospective study has reported its prevalence in Central Europe. This study aimed to evaluate the prevalence of keratoconus assessed with Scheimpflug imaging in a profile of general medicine practice in Poland.MethodsThis cross-sectional study collected data by inviting all patients aged 10–80 years subscribed to a single general practitioner in the Elbląg area, Poland. Corneal measurements were performed using a rotating Scheimpflug corneal tomography system. Three masked examiners established the diagnosis of keratoconus in the right or left eye. Fleiss’ kappa coefficient (κ) was used to qualitatively analyze the interexaminer agreement.ResultsOf 1,705 patients invited to the study, 771 agreed to participate (45.2%). The mean age of the 728 patients (60.6% female and 39.4% male) with gradable images in at least one eye was 53.6 ± 16.5 years. All of the examiners classified the same four cases as keratoconus (0.549%, 549 per 100,000, 95% confidence interval 150 to 1,400 per 100,000), of which two were bilateral. Fleiss’ kappa showed almost perfect agreement among the three examiners regarding the diagnostic decision (κ = 0.784, 95% confidence interval 0.750 to 0.817, p < 0.001). The keratoconus cases were all women (p = 0.106), aged 48, 69, 70, and 71 years old.ConclusionThe prevalence of keratoconus in this area was higher than that previously demonstrated in many European countries. Underestimation of the prevalence has been postulated but never demonstrated.     

An alternative plant-based fermented milk with kefir culture using apricot (Prunus armeniaca L.) seed extract: Changes in texture,volatiles and bioactivity during storage

The aim of the study was to produce kefir from apricot seed extract (ASE) as an alternative functional dairy food for vegans and lactose-intolerant people, the elderly, people with cardiovascular disease and diabetes. Kefir was produced by using cow's milk (100%, as control) and 100% ASE, and cow's milk was mixed with 25%, 50% and 75% (v/v) with ASE for kefir production and the resultant kefir samples were stored at 4 °C for 21 days. In proportion to the level of ASE, more yellowish color, lower viscosity, firmness, consistency and TPA values were developed. Additionally, a higher syneresis was observed in kefir samples with increasing levels of ASE. Angiotensin-converting enzyme-inhibitory (ACE-i) and antioxidant activities increased with the increasing levels of ASE used in the kefir production. The levels of individual free amino acids significantly changed by use of ASE and some amino acids including Gln, Gly and Arg dramatically increased, while others decreased by increasing levels of the ASE. Relatively lower levels of γ-amino butyric acid (GABA) were observed in the samples when compared to the free amino acids, and its concentration decreased by increasing levels of the ASE. The counts for yeasts, lactobacilli and lactococci increased with addition of ASE. Qualitative and quantitative differences were seen in volatile composition of kefir with the addition of ASE and acceptable sensory scores were obtained for all samples during storage. Concentrations of carboxylic acids decreased with increasing levels of ASE in kefir formula; however, the levels of alcohols and aldehydes increased. In conclusion, ASE can be considered in the formulation of fermented milk products or used purely in the production of plant-based fermented non-dairy beverages.     

Impact of controlled atmosphere storage on physiological quality of soybean seed

Soybean seed tends to lose its quality property if kept in inappropriate storage conditions. The aim of this work was to evaluate the effect of different oxygen (O₂) and carbon dioxide (CO₂) partial pressures, combined with different temperatures on the soybean seed physiological potential maintenance. In 2017, seed of the cultivars 8473 RSF and TECIRGA 6070RR were stored for 7 months under: [1] ambient air; controlled atmosphere (CA) with [2] 1 kPa O₂ + 0.04 kPa CO₂; [3] 2 kPa O₂ + 0.04 kPa CO₂; [4] 2 kPa O₂ + 30 kPa CO₂; and [5] 2 kPa O₂ + 80 kPa CO₂. In 2018, seed of NA 5909 RG and FEPAGRO 37RR were stored for 7 months under the following conditions: [1] ambient air; and CA with [2] 1 kPa O₂ + 0.04 kPa CO₂; [3] 1 kPa O₂ + 15 kPa CO₂; [4] 1 kPa O₂ + 30 kPa CO₂; [5] 2 kPa O₂ + 0.04 kPa CO_2. In both years the storage conditions were conducted at three temperatures (20, 25 and 30 °C). The seed were stored with moisture content between 11 and 11.5. The reduction of the O₂ until 1.0 kPa maintained higher germination, however, storage above 25 °C is not recommended. High CO₂ partial pressure did not have additional effects on physiological quality conservation compared to solely low O₂. Seed of 8473 RSF stored at 25 and 30 °C resulted in low germination, regardless of the CA condition. NA 5909 RG reached 80% of germination, when CA was used, regardless of temperature. The ambient air did not maintain the seed physiological quality when stored at 25 and 30 °C and CA may efficiently maintain the physiological quality of soybean seed after 7 months, even in the higher temperature for NA5909 RG, but not for the other cultivars.     

Modulation of native structural architecture and hydrodynamic properties of apple seed protein isolates

The study aimed to synthesize apple seed protein nanoparticles (APN) using planetary ball milling (PBM). On ball milling, protein nanoparticles displayed uniform size distribution with a hydrodynamic diameter of 490.21 nm. Electron microscopy showed irregular, disordered, and rough surfaces of nano-protein particles. FTIR analysis reveals increased β-turn and random coil in APN, indicating loss of ordered protein structure. Changes in secondary structure and microenvironment of amino-acid residues were also depicted by fluorescence quenching and circular dichroism. Owing to conformational changes, a notable decrease in thermal characteristics (∆H = 5.86 to 2.92 J/g) and % crystallinity (36.93 to 32.21%) was observed in APN. Moreover, PBM was found effective in improving the hydrodynamic properties of protein isolates. CLSM demonstrated that emulsions prepared with APN showed increased stability. These results suggest that mechanochemical reduction via ball-milling can be a powerful approach for fabricating nanoparticles with excellent structural and functional characteristics for use in various food systems.     

Application of central composite face centered design for the optimization of multiple-pass ultrasonication with mechanical homogenization (MPUMH) for carrot puree processing

Multiple-pass ultrasonication with mechanical homogenization was used as a novel method for the processing of carrot puree. The experimental design was based on the face centered composite design using response surface methodology. The carrot puree was assessed for its physical, chemical and nutraceutical properties. Significant difference (p ≤ 0.05) was recorded for bostwick consistency, sedimentation index, phase volume, color, particle size distribution and β-carotene content. Process optimization was based on the selected responses through a desirability function. Ultrasonication for 9 min followed by mechanical homogenization for 1 min, subjected to 3 passes, gave the optimum results with d (0.1), d (0.5) as 142.19 and 327.89 μm; β-carotene (1471.58 μg/g) and “a” value (21.42) with a composite desirability (0.85). The variation between the predicted and experimental values was <12%. This study is the first attempt towards using a combination of ultrasonication and mechanical homogenization for carrot puree processing.     

The associations between genetics,salt taste perception and salt intake in young adults

Food liking is one of the main determinants of food intake. Salt taste perception and preference, that play a role in liking of salt, may be genetically determined, although research in humans is scarce. The aim of this study was to explore the associations between genetics, salt taste perception, preference, self-reported salt habit and intake. The participants were young (18–35 years) and healthy adults (32 males and 63 females). Salt taste thresholds were determined with British Standard ISO3972:2011 methodology and salt taste preference by ratings of saltiness and pleasantness of tomato soup with salt concentrations reflecting salt content in foods. Self-reported salt habit was determined by asking participants how salty they usually eat their food and salt intake with two 24-hour 5-step multiple pass recalls. Genotyping for variants in the SCNN1B rs239345 and TRPV1 rs8065080 was performed. Participants homozygous for the minor allele of the rs8065080 had lower ratings of saltiness (p = 0.008) and higher ratings of pleasantness of soup (p = 0.027) when compared to major allele carriers. Preference for salt in soup was associated with salt habit (p = 0.003) and participants with high salt preference had higher salt intake compared to those with low salt preference (2236 ± 261 vs. 1543 ± 107 mg/1000 kcal, p = 0.017). TRPV1 rs8065080 may play a role in salt taste perception and preference, which should be confirmed in a larger sample size study. Hedonic appeal of salty food should be considered when providing personalised advice to change this behaviour.     

Potent antioxidant and anti-inflammatory bioactivities of fish roe-derived extracts

The regular consumption of fish and its products has been associated with decreased incidence of inflammatory conditions. Indeed, fish present several antioxidants and anti-inflammatory compounds (e.g., high levels of ω3 polyunsaturated fatty acids – PUFA). Therefore, this work explored fish roe derived from three different species, namely sardine, horse mackerel and sea bass, to produce new delivery devices. Aqueous and lipidic extracts were obtained using the Matyash method. Despite, the three aqueous extracts showed ability to scavenge peroxyl, hydroxyl and nitric oxide radicals, the ones derived from sardine roe were the most efficient. Thus, they were combined with sardine roe-derived lipidic extracts to prepare large unilamellar liposomes, designated as fishroesomes. The aqueous extracts, at non-cytotoxic concentrations, decreased the levels of pro-inflammatory mediators produced by stimulated macrophages, being these effects enhanced by its combination with liposomes. Consequently, the developed formulations could be promising natural options for the treatment of inflammatory diseases.Industrial relevanceFish roe has been increasingly included in the human diet due to its nutritional value (e.g., high levels of ω3 polyunsaturated fatty acids – PUFA) and health benefits. Therefore, this work used aqueous and lipidic extracts derived from roes of different fish, namely sardine, horse mackerel and sea bass, to produce novel, natural and safer formulations for the treatment of inflammatory conditions. The roes-derived aqueous extracts obtained using the Matyash method demonstrated significant antioxidant activity in comparison with the negative control (without compounds). Due to the overall higher antioxidant activity of sardine roe-derived aqueous extracts, they were used in combination with the lipidic extracts to produce large unilamellar liposomes. These sardine roe-derived formulations presented notable antioxidant and anti-inflammatory activities, at non-cytotoxic levels. Moreover, a complementary action between the two extracts was observed. Thus, this study provides important insights about the value of roe-derived aqueous and lipidic extracts that can be used to prepare new pharmaceutical formulations with bioactivity levels compatible with their medical use for the treatment of inflammatory diseases.     

Post-harvest food losses in a maize-based farming system of semi-arid savannah area of Tanzania

An assessment of post-harvest handling practices and food losses in a maize-based farming system in semi-arid areas of Central and Northern Tanzania was carried out in 2012. Seventeen crops were mostly cultivated by the farmers in the surveyed areas; maize (32%), sunflower (16%) and pigeon peas (12%) were the most cultivated while maize was the most stored. There are at least 7 months between two harvest seasons of each crop; while farmers sold the crops soon after harvest to cater for household expenditure (54%) and school fees (38%), the market prices increased significantly (P ≤ 0.05) within six months of storage. Most processing activities (winnowing, dehulling, drying, sorting and shelling) were carried out manually, almost entirely by women, but mechanized processing for maize, sunflower, millet, and sorghum were commonly practiced. Quantitative post-harvest losses of economic importance occur in the field (15%); during processing (13–20%), and during storage (15–25%). The main storage pests responsible for the losses are larger grain borers (Prostephanus truncatus), grain weevils (Sitophilus granarius) and, the lesser grain borer (Rhyzopertha dominica). Most of the farmers considered changes in weather (40%), field damage (33%), and storage pests (16%) as the three most important factors causing poor crop yields and aggravating food losses. However, survey results suggest that the farmers' poor knowledge and skills on post-harvest management are largely responsible for the food losses. 77% of the surveyed farmers reported inadequate household foods and 41% received food aid during the previous year. Increasing farmers' technical know-how on adaptation of the farming systems to climate variability, and training on post-harvest management could reduce food losses, and improve poverty and household food security.     

Traditional maize post-harvest management practices amongst smallholder farmers in Guatemala

Much of the maize that is produced in Guatemala is planted, harvested and handled via subsistence-oriented agricultural practices, strongly connected to Mayan heritage. This post-harvest assessment study was done to characterize the current practices used in the region of Huehuetenango, Guatemala, in order to identify the different grain handling practices in the region as well as possible factors contributing to post-harvest losses of maize. A total of 280 families representing 14 rural communities were surveyed through interviews. Survey revealed that most (88%) of interviewed farmers prefer to dry the maize cobs after harvest by laying them in stacks exposed to direct sunlight. After drying, harvested maize is stored until consumption along with purchased maize kernels from the market. Among storage practices, 62% of surveyed families store the maize as shelled kernels; while 38% store it on cobs. When storing shelled maize, bags are the preferred containers among 81% of farmers, while only 14% use metal silos. Among farmers who stored maize on cobs, 74% use the tapanco as the preferred storage structure. Forty-one percent of farmers indicated storing the maize for at least 4 months. During the storage time, 61% of farmers perform grain quality checks once a week. Moreover, 65% perform pest control during storage; however, in most cases, the control is not preventive but corrective. For 49% of farmers, the main cause of loss between harvest and consumption is the mishandling of grain moisture, leading to insect and fungal infestation. With this data, it was possible to identify diverse maize harvesting, drying, storage and consumption practices within the studied communities. Understanding the traditional post-harvest practices will help better design intervention steps to improve these practices and to increase food security and food safety for smallholder farmers in the Guatemalan Highlands.     

On-farm comparison of different postharvest storage technologies in a maize farming system of Tanzania Central Corridor

Seven methods for storing maize were tested and compared with traditional storage of maize in polypropylene bags. Twenty farmers managed the experiment under their prevailing conditions for 30 weeks. Stored grain was assessed for damage every six weeks. The dominant storage insect pests identified were the Maize weevil (Sitophilus zeamais) and the Red flour beetle (Tribolium castaneum). The moisture content of grain in hermetic conditions increased from 12.5 ± 0.2% at the start of storage to a range of 13.0 ± 0.2–13.5 ± 0.2% at 30 weeks. There was no significant difference (F = 87.09; P < 0.0001) regarding insect control and grain damage between hermetic storage and fumigation with insecticides. However, the insecticide treatment of polypropylene yarn (ZeroFly^®) did not control the insect populations for the experimental period under farmers' management. Grain damage was significantly lower in hermetic storage and fumigated grain than ZeroFly^® and polypropylene bags without fumigation. No significant difference in grain damage was found between airtight treatment alone and when combined with the use of insecticides. During storage, S. zeamais was predominant and could be of more economic importance than T. castaneum as far as maize damage is concerned. At 30 weeks, the germination rate of grain stored with insecticides or in hermetic storage (68.5 ± 3.6% to 81.4 ± 4.0%) had not significantly reduced from the rate before storage (F = 15.55; P < 0.0001) except in ZeroFly^®, also in polypropylene bags without treatment. Even though such bags did not control storage pests, farmers still liked this cheap technology. Hermetic storage techniques can be recommended to farmers without the use of insecticides provided they are inexpensive, and the proper application of technologies is ensured.